ID   CHLB_PINST              Reviewed;         511 AA.
AC   Q95666;
DT   01-NOV-1997, integrated into UniProtKB/Swiss-Prot.
DT   01-FEB-1997, sequence version 1.
DT   03-AUG-2022, entry version 81.
DE   RecName: Full=Light-independent protochlorophyllide reductase subunit B {ECO:0000255|HAMAP-Rule:MF_00353};
DE            Short=DPOR subunit B {ECO:0000255|HAMAP-Rule:MF_00353};
DE            Short=LI-POR subunit B {ECO:0000255|HAMAP-Rule:MF_00353};
DE            EC=1.3.7.7 {ECO:0000255|HAMAP-Rule:MF_00353};
GN   Name=chlB {ECO:0000255|HAMAP-Rule:MF_00353};
OS   Pinus strobus (Eastern white pine).
OG   Plastid; Chloroplast.
OC   Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC   Spermatophyta; Pinopsida; Pinidae; Conifers I; Pinales; Pinaceae; Pinus;
OC   Pinus subgen. Strobus.
OX   NCBI_TaxID=3348;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=WV103;
RX   PubMed=8305874; DOI=10.2307/3869697;
RA   Li J., Goldschmidt-Clermont M., Timko M.P.;
RT   "Chloroplast-encoded chlB is required for light-independent
RT   protochlorophyllide reductase activity in Chlamydomonas reinhardtii.";
RL   Plant Cell 5:1817-1829(1993).
CC   -!- FUNCTION: Component of the dark-operative protochlorophyllide reductase
CC       (DPOR) that uses Mg-ATP and reduced ferredoxin to reduce ring D of
CC       protochlorophyllide (Pchlide) to form chlorophyllide a (Chlide). This
CC       reaction is light-independent. The NB-protein (ChlN-ChlB) is the
CC       catalytic component of the complex. {ECO:0000255|HAMAP-Rule:MF_00353}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=2 ADP + chlorophyllide a + oxidized 2[4Fe-4S]-[ferredoxin] + 2
CC         phosphate = 2 ATP + 2 H2O + protochlorophyllide a + reduced 2[4Fe-
CC         4S]-[ferredoxin]; Xref=Rhea:RHEA:28202, Rhea:RHEA-COMP:10002,
CC         Rhea:RHEA-COMP:10004, ChEBI:CHEBI:15377, ChEBI:CHEBI:30616,
CC         ChEBI:CHEBI:33722, ChEBI:CHEBI:33723, ChEBI:CHEBI:43474,
CC         ChEBI:CHEBI:83348, ChEBI:CHEBI:83350, ChEBI:CHEBI:456216; EC=1.3.7.7;
CC         Evidence={ECO:0000255|HAMAP-Rule:MF_00353};
CC   -!- COFACTOR:
CC       Name=[4Fe-4S] cluster; Xref=ChEBI:CHEBI:49883;
CC         Evidence={ECO:0000255|HAMAP-Rule:MF_00353};
CC       Note=Binds 1 [4Fe-4S] cluster per heterodimer. The cluster is bound at
CC       the heterodimer interface by residues from both subunits.
CC       {ECO:0000255|HAMAP-Rule:MF_00353};
CC   -!- PATHWAY: Porphyrin-containing compound metabolism; chlorophyll
CC       biosynthesis (light-independent). {ECO:0000255|HAMAP-Rule:MF_00353}.
CC   -!- SUBUNIT: Protochlorophyllide reductase is composed of three subunits;
CC       ChlL, ChlN and ChlB. Forms a heterotetramer of two ChlB and two ChlN
CC       subunits. {ECO:0000255|HAMAP-Rule:MF_00353}.
CC   -!- SUBCELLULAR LOCATION: Plastid, chloroplast.
CC   -!- SIMILARITY: Belongs to the ChlB/BchB/BchZ family. {ECO:0000255|HAMAP-
CC       Rule:MF_00353}.
CC   ---------------------------------------------------------------------------
CC   Copyrighted by the UniProt Consortium, see https://www.uniprot.org/terms
CC   Distributed under the Creative Commons Attribution (CC BY 4.0) License
CC   ---------------------------------------------------------------------------
DR   EMBL; U02533; AAB06369.1; -; Genomic_DNA.
DR   AlphaFoldDB; Q95666; -.
DR   SMR; Q95666; -.
DR   UniPathway; UPA00670; -.
DR   GO; GO:0009507; C:chloroplast; IEA:UniProtKB-SubCell.
DR   GO; GO:0051539; F:4 iron, 4 sulfur cluster binding; IEA:UniProtKB-UniRule.
DR   GO; GO:0005524; F:ATP binding; IEA:UniProtKB-UniRule.
DR   GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR   GO; GO:0016730; F:oxidoreductase activity, acting on iron-sulfur proteins as donors; IEA:InterPro.
DR   GO; GO:0016636; F:oxidoreductase activity, acting on the CH-CH group of donors, iron-sulfur protein as acceptor; IEA:UniProtKB-UniRule.
DR   GO; GO:0036068; P:light-independent chlorophyll biosynthetic process; IEA:UniProtKB-UniPathway.
DR   GO; GO:0019685; P:photosynthesis, dark reaction; IEA:InterPro.
DR   Gene3D; 1.10.8.550; -; 1.
DR   HAMAP; MF_00353; ChlB_BchB; 1.
DR   InterPro; IPR013580; LI-POR_suB-like_C.
DR   InterPro; IPR000510; Nase/OxRdtase_comp1.
DR   InterPro; IPR042298; P-CP_red_C.
DR   InterPro; IPR005969; Protochl_reductB.
DR   InterPro; IPR016209; Protochlorophyllide_Rdtase.
DR   Pfam; PF00148; Oxidored_nitro; 1.
DR   Pfam; PF08369; PCP_red; 1.
DR   PIRSF; PIRSF000163; PCP_ChlB; 1.
DR   TIGRFAMs; TIGR01278; DPOR_BchB; 1.
PE   3: Inferred from homology;
KW   4Fe-4S; ATP-binding; Chlorophyll biosynthesis; Chloroplast; Iron;
KW   Iron-sulfur; Metal-binding; Nucleotide-binding; Oxidoreductase;
KW   Photosynthesis; Plastid.
FT   CHAIN           1..511
FT                   /note="Light-independent protochlorophyllide reductase
FT                   subunit B"
FT                   /id="PRO_0000219838"
FT   ACT_SITE        297
FT                   /note="Proton donor"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00353"
FT   BINDING         36
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /ligand_note="ligand shared with heterodimeric partner"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00353"
FT   BINDING         432..433
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00353"
SQ   SEQUENCE   511 AA;  57802 MW;  4BAB513433FDF874 CRC64;
     MKLAYWMYAG PAHIGTLRVA SSFKNVHAIM HAPLGDDYFN VMRSMLERER NFTPATASIV
     DRHVLARGSR KRVVDNILRK DKEESPDLII LTPTCTSSIL QEDLKNFVDR ASIISDCNVI
     FADVDHYQVN EIQAADRTLE QVVRYYLDKS HTLDQFVTDA PSVNIIGILT LGFHNRHDCR
     ELRRLLKDLD IRINQIIPEG GSVEDPKNLP KARFNLIPYR EVGLMTAMYL NKEFGMPYVS
     TTPMGAVDMA ECIRQIKKSL DILAAPILSS KRVDYESYID GQTRFVSQAA WFSRSIDCQN
     FTGKETVVFG DATHAASITK ILAREMGIRV SCTGTYCKHD AEWFKEQIQD FCDEMIITDD
     HAEVGDIIAR VEPSAIFGTQ MERHIGKRLE IPCGVISAPA HIQNFSLGYR PFLGYEGTNQ
     IADLVYNSFA LGMEDHLLEI FCGHDTKEIM TKSLSTDISP IWDPESRQEL GKIPRFVRDE
     VKINTEKFAR RKGLLNVTVE VMHAAKEALS A